What is the EEA?
In order to understand the precise definition of the EEA, we must understand the definition of a selection pressure. Many of the misconceptions about the EEA can be avoided by adhering closely to the precise definition of the EEA derived from the theory of natural selection. As noted above, the EEA is the set of all selection pressures faced by an organism’s ancestors over ‘recent’ evolutionary time (i.e., over approximately the last 1000-10,000 generations). To understand what a selection pressure is, we must understand how a mutation spreads in a population. It must alter the phenotype in some way that enhances reproduction (ignoring drift and other similar processes for the moment). As emphasized elsewhere in this FAQ, reproduction is an enormously complex process; that it happens at all is a near miracle. Reproduction involves a vast number of physical processes that must proceed correctly if reproduction is to be successful. Given the design of an organism, given all the physical
